1,2-Diphenyl-3,5-ditrifluoroacetyloxy-4-butyl-5-hydroxy-3-pyrazoline

ABSTRACT

The compound 1,2-Diphenyl-3,5-ditrifluoroacetyloxy-4-butyl-5-hydroxy-3-pyrazoline is disclosed as an intermediate useful in the preparation of selected pro-phenylbutazone derivatives. 
     Such selected pro-phenylbutazone derivatives are novel, transient, pro-drug forms of phenylbutazone and oxyphenbutazone having the following formulae wherein R, R 2 , R 4 , R 5 , X and Y are as defined herein: ##STR1## The above-identified compounds exhibit anti-inflammatory activity in warm-blooded animals. Upon administration to warm-blooded animals, these compounds pass through the gastrointenstinal tract and cleave in the bloodstream, thus releasing phenylbutazone or oxyphenbutazone in an anti-inflammatory effective amount at their therapeutic site or sites of activity.

This is a division, of application Ser. No. 664,698, filed Mar. 8, 1976,now U.S. Pat. No. 4,036,845, which in turn is a division of applicationSer. No.538,903, filed Jan. 6, 1975, now U.S. Pat. No. 3,957,803.

BACKGROUND OF THE INVENTION

1. Field of the Invention

The present invention is directed to novel, transient, pro-drugs usefulas anti-inflammatory agents in warm-blooded animals (e.g., humans). Moreparticularly, the present invention extends to certain novel, transient,pro-drug forms of phenylbutazone and oxyphenbutazone, known and provenanti-inflammatory agents.

For the purposes of this application, the term "pro-drug" denotes aderivative of a known and proven prior art compound (i.e.,phenylbutazone and oxyphenbutazone) which derivative, when administeredto a warm-blooded animal, "cleaves" in such a manner as to release theproven drug form and permit the same to attain a higher therapeuticlevel and/or reduced toxic action than that which could be attained ifthe proven drug form per se was administered.

The term "transient" denotes enzymatic and/or chemical hydrolytic"cleavage" of the compounds of this invention in such a manner that theproven drug form (phenylbutazone or oxyphenbutazone) is released and theremaining "cleaved" moiety reamins nontoxic and metabolized in such amanner that nontoxic, metabolic products are produced.

2. Description of the Prior Art

Phenylbutazone and oxyphenbutazone represent non-hormonalanti-inflammatory agents, highly effective in the treatment ofrheumatoid disorders and other non-specific inflammatory conditions.Chemically, phenylbutazone and oxyphenbutazone are4-butyl-1,2-diphenyl-3,5-pyrazolidinedione and4-butyl-2-(p-hydroxyphenyl)-1-phenyl-3,5-pyrazolidinedione,respectively.

The analgesic, antipyretic and anti-inflammatory actions ofphenylbutazone and oxyphenbutazone are manifested as prompt relief ofpain, lysis of fever and diminution of swelling, tenderness and localheat. The dosage regimen will vary with the size of the individualtreated as well as the individual's needs. However, conventionally, aninitial daily dose in adults ranges from 300 to 600 mg, divided intothree or four equal doses.

While phenylbutazone and oxyphenbutazone are highly recognizedanti-inflammatory agents, their respective solubilities cause extremegastric irritation which is manifested by blood loss from thegastrointestinal (GI) tract. Essentially, phenylbutazone andoxyphenbutazone are relatively insoluble in the GI tract. In order toalleviate this situation, numerous salts and complexes of thesecompounds have been prepared. However, these new derivatives revert backto phenylbutazone and oxyphenbutazone, respectively, extremely rapidlyin the GI tract. As a result, phenylbutazone and oxyphenbutazone arereleased in the GI tract (not in the bloodstream), and because of theirinsolubility therein, (1) they are not readily absorbed into thebloodstream, and (2) extreme GI irritation is observed. In addition,compounds specifically related to those of formula (I) above have beenprepared in the past (see, U.S. Pat. Nos. 2,905,694 and 3,607,881 andSpanish Pat. No. 379,995). However, these compounds are relativelyinsoluble as well, and, therefore, offer no advantage over the otherprior art compounds. That is, these compounds, being relativelyinsoluble are not absorbed readily through the GI tract. Consequently,they will not readily release phenylbutazone in the bloodstream and willnot minimize GI irritation.

SUMMARY OF THE INVENTION

It is, therefore, one object of the present invention to provideselected derivatives of phenylbutazone and oxyphenbutazone foradministration to warm-blooded animals (e.g., humans) which will passthrough the gastrointestinal track and subsequently "cleave" uponabsorption into the bloodstream to release phenylbutazone andoxyphenbutazone in an anti-inflammatory effective amount at theirtherapeutic site or sites of activity.

It is another object of the present invention to provide selectedderivatives of phenylbutazone and oxyphenbutazone as above describedwhich, in addition to passing through the GI tract, dramaticallyminimizes irritation therein.

It is still another object of the present invention to providederivatives of phenylbutazone and oxyphenbutazone as previouslydescribed, wherein following "cleavage" of the pro-drug, thus releasingphenylbutazone or oxyphenbutazone at their therapeutic site or sites ofactivity, the pro-drug moiety (that which is not related to the parentcompound) is metabolized in a nontoxic fashion.

All the foregoing objects are obtained with selected transient, pro-drugforms of phenylbutazone and oxyphenbutazone as provided below: ##STR2##wherein R represents a member selected from the group consisting of a C₁-C₂ O-alkylsulfonyl group, an aryl(phenyl, p-tolyl, naphthyl)sulfonylgroup, a nicotinoyl group, an iso-nicotinoyl group, a picolinoyl group,an N-protected naturally occurring amino acid residue, wherein theprotective group on the amino group of the amine acid residue isremovable via hydrogenolysis or hydrolysis, and an amino acid residuecontaining a C₁ -C₂ N,N-dialkylamino or a C₄ -C₆ cycloalkylamino group.##STR3## wherein X and Y each represent a member selected from the groupconsisting of a hydrogen atom and a --OR₁ group, with the proviso thateither X or Y is a hydrogen atom and that R₂ is a member selected fromthe same or different groups represented by R₁ ; and wherein R₁represents a member selected from the group consisting of a hydrogenatom, a C₁ -C₂ O-alkylsulfonyl group, an aryl(phenyl, p-tolyl,naphthyl)sulfonyl group, a --CH₂ COOM group, wherein M represents analkali or alkaline earth metal (Na, K, Ca, Mg); a --CO--R₃ group,wherein R₃ represents a member selected from the group consisting of astraight or branched C₁ -C₅ alkyl group, a C₁ -C₂ alkoxy group, a phenylgroup, a substituted phenyl group whose substituents are selected fromthe group consisting of a 2,3, or 4-hydroxy group, a 2,3, or 4-acetyloxygroup, and a 2,3, or 4-acetylamino group, a 2,3, or 4-pyridyl group, a1,2, or 5-imidazolyl group, a residue of an N-protected naturallyoccurring amino acid, wherein the protective group on the amino group ofthe amino acid is removable via hydrogenolysis or hydrolysis, and anamino acid residue containing a C₁ -C₂ N, N-dialkylamino or C₄ -C₅cycloalkylamino group. ##STR4## wherein X or Y represents a memberselected from the group consisting of a hydrogen atom and a --OR₁ group,wherein R₁ is as defined above with the proviso that either X or Y is ahydrogen atom; wherein R₄ represents a member selected from the groupconsisting of a hydrogen atom, a C₁ -C₅ alkyl group, an aryl group(phenyl, styryl), a 2,3, or 4-methoxyphenyl group, and a -CH═CH₂ group;and wherein R₅ represents a member selected from the group consisting ofa --OOC-R₆ group, a ##STR5## group, and a -COOM group, wherein Mrepresents an alkali or alkaline earth metal (Na, K, Ca, Mg), wherein R₆represents a member selected from the group consisting of R₄ as definedabove, with the proviso that R₆ cannot be a hydrogen atom, and whereinR₇ and R₈ each represent a C₁ -C₃ alkyl group.

With respect to the phrases "N-protected naturally occurring amino acid"and "amino acid residue" used above, any conventional amino aciddisclosed in U.S. Pat. No. 3,803,120 - Felix, et al will suffice.Illustrative of N-protective groups are those described in "SyntheticPeptides", Vol. 1, p. 5 by George R. Pettit (1970) and "Chemistry of theAmino Acids", Vol. 2, p. vi by Jesse P. Greenstein and Milton Winitz(1961).

While the foregoing objects are met with all the compounds of formulas(I) through (III) above, nevertheless, certain selected compounds arepreferred as set out below:

(1) 1,2-Diphenyl-4-butyl-5-(3'-carboxypyridyl)-4-pyrazolin-3-one

(2) 1,2-Diphenyl-4-butyl-5-(2'-carboxypyridyl)-4-pyrazolin-3-one

(3) 1,2-Diphenyl-4-butyl-5-(4'-carboxypyridyl)-4-pyrazolin-3-one

(4) 1,2-Diphenyl-4-butyl-5-pivalyloxy-4-pyrazolin-3-one

(5) 1,2-Diphenyl-4-butyl-5-(N,N-dimethylcarbamoyloxy)-4-pyrazolin-3-one

(6) 1,2-Diphenyl-4-butyl-5-(N,N-diethylcarbamoyloxy)-4-pyrazolin-3-one

(7) 1,2-Diphenyl-4-butyl-5-(N-formylglycyloxy)-4-pyrazolin-3-one

(8) 1,2-Diphenyl-4-butyl-5-(N-ethoxycarbonylglycyloxy)-4-pyrazolin-3-one

(9)1,2-Diphenyl-4-butyl-5-(N-benzyloxycarbonylglycyloxy)-4-pyrazolin-3-one

(10)1,2-Diphenyl-4-butyl-5-(4'-methylphenylsulfonyloxy)-4-pyrazolin-3-one

(11) 1,2-Diphenyl-4-butyl-5-methylsulfonyloxy-4-pyrazolin-3-one

(12) 1,2-Diphenyl-4-butyl-5-ethylsulfonyloxy-4-pyrazolin-3-one

(13) 1,2-Diphenyl-4-butyl-5-camphorsulfonyloxy-4-pyrazolin-3-one

(14) 1,2-Diphenyl-4-butyl-5-pivalyloxymethoxy-4-pyrazolin-3-one

(15) 1,2-Diphenyl-4-butyl-5-benzoyloxymethoxy-4-pyrazolin-3-one

(16) 1,2-Diphenyl-4-butyl-5-cinnamoyloxymethoxy-4-pyrazolin-3-one

(17) 1,2-Diphenyl-4-butyl-5-benzoyloxybenzyloxy-4-pyrazolin-3-one

(18) 1,2-Diphenyl-4-butyl-5-acetyloxymethoxy-4-pyrazolin-3-one

(19)1,2-Diphenyl-4-butyl-5-(N,N-dimethylcarbamoylmethoxy)-4-pyrazolin-3-one

(20)1,2-Diphenyl-4-butyl-5-(N,N-diethylcarbamoylmethoxy)-4-pyrazolin-3-one

(21)1-(4'-Acetyloxyphenyl)-2-phenyl-4-butyl-5-acetyloxy4-pyrazolin-3-one

(22)1-(4'-Acetyloxyphenyl)-2-phenyl-4-butyl-5-(3'-carboxypyridyl)-4-pyrazolin-3-one

(23)1-(4'-Acetyloxyphenyl)-2-phenyl-4-butyl-5-(2'-carboxypyridyl)-4-pyrazolin-3-one

(24)1-(4'-Acetyloxyphenyl)-2-phenyl-4-butyl-5-(4'-carboxypyridyl)-4-pyrazolin-3-one

(25)1-(4'-Acetyloxyphenyl)-2-phenyl-4-butyl-5-pivalyloxy-4-pyrazolin-3-one

(26)1-(4'-Acetyloxyphenyl)-2-phenyl-4-butyl-5-(N,N-dimethylcarbamoyloxy)-4-pyrazolin-3-one

(27)1-(4'-Acetyloxyphenyl)-2-phenyl-4-butyl-5-(N,N-diethylcarbamoyloxy)-4-pyrazolin-3-one

(28)1-(4'-Acetyloxyphenyl)-2-phenyl-4-butyl-5-(N-formylglycyloxy)-4-pyrazolin-3-one

(29)1-(4'-Acetyloxyphenyl)-2-phenyl-4-butyl-5-(N-ethoxycarbonylglycyloxy)-4-pyrazolin-3-one

(30)1-(4'-Acetyloxyphenyl)-2-phenyl-4-butyl-5-(N-benzyloxycarbonylglycyloxy)-4-pyrazolin-3-one

(31)1-(4'-Acetyloxyphenyl)-2-phenyl-4-butyl-5-(4'-methylphenylsulfonyloxy)-4-pyrazolin-3-one

(32)1-(4'-Acetyloxyphenyl)-2-phenyl-4-butyl-5-methylsulfonyloxy-4-pyrazolin-3-one

(33)1-(4'-Acetyloxyphenyl)-2-phenyl-4-butyl-5-ethylsulfonyloxy-4-pyrazolin-3-one

(34)1-(4'-Acetyloxyphenyl)-2-phenyl-4-butyl-5-camphorsulfonyloxy-4-pyrazolin-3-one

(35)1-(4'-Acetyloxyphenyl)-2-phenyl-4-butyl-5-pivalyloxymethoxy-4-pyrazolin-3-one

(36)1-(4'-Acetyloxyphenyl)-2-phenyl-4-butyl-5-benzoyloxymethoxy-4-pyrazolin-3-one

(37)1-(4'-Acetyloxyphenyl)-2-phenyl-4-butyl-5-cinnamoyloxymethoxy-4-pyrazolin-3-one

(38)1-(4'-Acetyloxyphenyl)-2-phenyl-4-butyl-5-benzoyloxybenzyloxy-4-pyrazolin-3-one

(39)1-(4'-Acetyloxyphenyl)-2-phenyl-4-butyl-5-acetyloxymethoxy-4-pyrazolin-3-one

(40)1-Phenyl-2-(4'-acetyloxyphenyl)-4-butyl-5-acetyloxy-4-pyrazolin-3-one

(41)1-Phenyl-2-(4'-acetyloxyphenyl)-4-butyl-5-(3'-carboxypyridyl)-4-pyrazolin-3-one

(42)1-Phenyl-2-(4'-acetyloxyphenyl)-4-butyl-5-(2'-carboxypyridyl)-4-pyrazolin-3-one

(43)1-Phenyl-2-(4'-acetyloxyphenyl)-4-butyl-5-(4'-carboxypyridyl)-4-pyrazolin-3-one

(44)1-Phenyl-2-(4'-acetyloxyphenyl)-4-butyl-5-pivalyloxy-4-pyrazolin-3-one

(45)1-Phenyl-2-(4'-acetyloxyphenyl)-4-butyl-5-(N,N-dimethylcarbamoyloxy)-4-pyrazolin-3-one

(46)1-Phenyl-2-(4'-acetyloxyphenyl)-4-butyl-5-(N,N-diethylcarbamoyloxy)-4-pyrazolin-3-one

(47)1-Phenyl-2-(4'-acetyloxyphenyl)-4-butyl-5-(N-formylglycyloxy-4-pyrazolin-3-one

(48)1-Phenyl-2-(4'-acetyloxyphenyl)-4-butyl-5-(N-ethoxycarbonylglycyloxy)-4-pyrazolin-3-one

(49)1-Phenyl-2-(4'-acetyloxyphenyl)-4-butyl-5-(N-benzyloxycarbonylglycyloxy)-4-pyrazolin-3-one

(50)1-Phenyl-2-(4'-acetyloxyphenyl)-4-butyl-5-(4'-methylphenylsulfonyloxy)-4-pyrazolin-3-one

(51)1-Phenyl-2-(4'-acetyloxyphenyl)-4-butyl-5-methylsulfonyloxy-4-pyrazolin-3-one

(52)1-Phenyl-2-(4'-acetyloxyphenyl)-4-butyl-5-ethylsulfonyloxy-4-pyrazolin-3-one

(53)1-Phenyl-2-(4'-acetyloxyphenyl)-4-butyl-5-camphorsulfonyloxy-4-pyrazolin-3-one

(54)1-Phenyl-2-(4'-acetyloxyphenyl)-4-butyl-5-pivalyloxymethoxy-4-pyrazolin-3-one

(55)1-Phenyl-2-(4'-acetyloxyphenyl)-4-butyl-5-benzoyloxymethoxy-4-pyrazolin-3-one

(56)1-Phenyl-2-(4'-acetyloxyphenyl)-4-butyl-5-cinnamoyloxymethoxy-4-pyrazolin-3-one

(57)1-Phenyl-2-(4'-acetyloxyphenyl)-4-butyl-5-benzoyloxybenzyloxy-4-pyrazolin-3-one

(58)1-Phenyl-2-(4'-acetyloxyphenyl)-4-butyl-5-acetyloxymethoxy-4-pyrazolin-3-one

(59)1-(4'-Benzoyloxyphenyl)-2-phenyl-4-butyl-5-benzoyloxy-4-pyrazolin-3-one

(60)1-(4'-Benzoyloxyphenyl)-2-phenyl-4-butyl-5-acetyloxy-4-pyrazolin-3-one

(61)1-(4'-Benzoyloxyphenyl)-2-phenyl-4-butyl-5-(3'-carboxypyridyl)-4-pyrazolin-3-one

(62)1-(4'-Benzoyloxyphenyl)-2-phenyl-4-butyl-5-(2'-carboxypyridyl)-4-pyrazolin-3-one

(63)1-(4'-Benzoyloxyphenyl)-2-phenyl-4-butyl-5-(4'-carboxypyridyl)-4-pyrazolin-3-one

(64)1-(4'-Benzoyloxyphenyl)-2-phenyl-4-butyl-5-pivalyloxy-4-pyrazolin-3-one

(65)1-(4'-Benzoyloxyphenyl)-2-phenyl-4-butyl-5-(N,N-dimethylcarbamoyloxy)-4-pyrazolin-3-one

(66)1-(4'-Benzoyloxyphenyl)-2-phenyl-4-butyl-5-(N,N-diethylcarbamoyloxy)-4-pyrazolin-3-one

(67)1-(4'-Benzoyloxyphenyl)-2-phenyl-4-butyl-5-(N-formylglycyloxy)-4-pyrazolin-3-one

(68)1-(4'-Benzoyloxyphenyl)-2-phenyl-4-butyl-5-(N-ethoxycarbonylglycyloxy)-4-pyrazolin-3-one

(69)1-(4'-Benzoyloxyphenyl)-2-phenyl-4-butyl-5-(N-benzyloxycarbonylglycyloxy)-4-pyrazolin-3-one

(70)1-(4'-Benzoyloxyphenyl)-2-phenyl-4-butyl-5-(4'-methylphenylsulfonyloxy)-4-pyrazolin-3-one

(71)1-(4'-Benzoyloxyphenyl)-2-phenyl-4-butyl-5-methylsulfonyloxy-4-pyrazolin-3-one

(72)1-(4'-Benzoyloxyphenyl)-2-phenyl-4-butyl-5-ethylsulfonyloxy-4-pyrazolin-3-one

(73)1-(4'-Benzoyloxyphenyl)-2-phenyl-4-butyl-5-camphorsulfonyloxy-4-pyrazolin-3-one

(74)1-(4'-Benzoyloxyphenyl)-2-phenyl-4-butyl-5-pivalyloxymethoxy-4-pyrazolin-3-one

(75)1-(4'-Benzoyloxyphenyl)-2-phenyl-4-butyl-5-benzoyloxymethoxy-4-pyrazolin-3-one

(76)1-(4'-Benzoyloxyphenyl)-2-phenyl-4-butyl-5-cinnamoyloxymethoxy-4-pyrazolin-3-one

(77)1-(4'-Benzoyloxyphenyl)-2-pheny-4-butyl-5-benzoyloxybenzyloxy-4-pyrazolin-3-one

(78)1-(4'-Benzoyloxyphenyl)-2-phenyl-4-butyl-5-acetyloxymethoxy-4-pyrazolin-3-one

The above compounds can alternately be named as1,2-dihydro-3H-pyrazol-3-one derivatives.

The compounds of the present invention are prepared in a convenientmanner as outlined below.

PREPARATION OF THE COMPOUNDS OF FORMULA (I) METHOD "A" (PREPARATION OFTHOSE COMPOUNDS EXCLUSIVE OF THE SULFONATE DERIVATIVES):

First, phenylbutazone is dissolved in a sight excess of trifluoroaceticanhydride (TFAA) at room temperature and standard pressure for a periodof 1 - 2 hours. Then, the resulting intermediate compound is treatedwith a slight excess of the acid anhydride of "R" in Formula (I). Theexcess acid is neutralized via extraction of a dichloromethane solutionof the above reaction mixture with three equivalents of an aqueousinorganic base of an alkali or alkaline earth metal, such as KOH, NaOH,NaHCO₃. The final compound is isolated by evaporation of thedichloromethane and purification is conventionally carried out viarecrystallization from a chloroform/heptane mixture or any conventionalhalogenated hydrocarbon solvent (e.g., chloroform, dichloromethane,etc.), or any equivalent solvent.

The process described herein under Method "A" is deemed novel by thepresent inventors, and as such, this particular process is includedwithin the inventive scope of this invention. Moreover, the intermediateproduct derived from the reaction between phenylbutazone andtrifluoroacetic anhydride(1,2-diphenyl-3,5-ditrifluoroacetyloxy-4-butyl-5-hydroxy-3-pyrazoline)is also deemed novel by the present inventors and is included withintheir invention as well.

METHOD " B" (PREPARATION OF THE SULFONATE DERIVATIVES:

A suitable salt of phenylbutazone (K, Na, triethylammonium, Tl (I),etc.) is reacted with the corresponding sulfonyl chloride in an inertorganic solvent, such as ether, dimethylformamide, tetrahydrofuran(THF), benzene, etc. over a period of 1 to 24 hours, at room temperatureand standard pressure. The halide salt is then filtered off or washedfrom the reaction mixture, and the final product is isolated followingevaporation of the dried solvent. If necessary, the final product can beconventionally recrystallized.

PREPARATION OF THE COMPOUNDS OF FORMULA (II) METHOD "A" (WHEN R₁ AND R₂ARE IDENTICAL AND OTHER THAN --CH₂ COOM:

Oxyphenbutazone is mixed with two equivalents of a conventionaltrialkylamine, such as triethylamine at room temperature and standardpressure, in the presence of a suitable solvent (e.g., a halogenatedhydrocarbon, such as chloroform, or benzene). The resulting mixture isthen treated with two equivalents of an appropriate acyl chloride (e.g.,acetyl chloride, benzoyl chloride, or the like) at room temperature andstandard pressure for a period of 1 to 24 hours. After washing withwater and drying the solvent with sodium sulfate, the solvent isevaporated to give the final product. If necessary, the final productcan be recrystallized by conventional procedures.

METHOD "B" (WHEN R₁ AND R₂ ARE NOT THE SAME AND OTHER THAN --CH₂ COOM)

The R₁ moiety of Formula (II) is introduced by reacting oxyphenbutazonewith an acyl chloride (e.g., acetyl chloride, benzoyl chloride, etc.) oran acyl anhydride in the presence of an acid catalyst such asp-toluenesulfonic acid, sulfosalicyclic acid or the like in the presenceof an inert organic solvent such as a carboxylic acid (e.g., aceticacid), ethyl acetate, toluene, benzene, etc. After neutralization of thecatalyst, the final product is obtained via solvent evaporation. Ifnecessary, conventional recrystallization of the final product can becarried out.

In the second step, the R₂ moiety of Formula (II) is introduced via theprocedure of Method "A" of Formula (II) above, but using only oneequivalent of triethylamine. In this step the use of only one equivalentof triethylamine is critical to the introduction of the R₂ moiety.

METHOD "C" (WHEN R₁ AND/OR R₂ EQUAL -CH₂ COOM):

First, a suitable disalt of oxyphenbutazone (e.g., Na, K, T1 (I) isreacted with chloroacetic acid at room temperature and standard pressurefor a period of 1 to 24 hours in water or a suitable inert organicsolvent, such as THF, acetone, or dichloromethane. After filtering offthe organic halides, the final compound is isolated via solventevaporation. The dicarboxylic acid formed can be converted to its M saltby simply adding two equivalents of an M-OH base in alcohol followed bysolvent evaporation, wherein M represents an alkali or alkaline earthmetal as described earlier.

THE COMPOUNDS OF FORMULA (III) METHOD "A" (WHEN X AND Y ARE BOTHHYDROGEN)

A suitable salt of phenylbutazone (e.g., alkali or alkaline earth metalsalt, Tl (I), or triethylammonium salt) is reacted in an inert organicsolvent, such as acetone, dichloromethane, THF, etc. with a compound ofthe Formula: ##STR6## wherein R₄ and R₅ are as defined above in Formula(III), and wherein X represents a halogen atom such as chlorine,bromine, or iodine. The reaction is carried out at standard pressure andat the reflux temperature of the solvent employed for a period of 1 to24 hours. After filtering or washing off the halogen salt formed, thefinal product is isolated by evaporation of the solvent. If necessary,the final product may be recrystallized conventionally.

During this reaction, in many instances, in addition to obtaining thetitle compounds of Formula (III), a C₄ isomer of the title compoundshaving the following formula can also be obtained: ##STR7## wherein R₄and R₅ are as defined above.

METHOD "B" (WHEN X OR Y ARE NOT HYDROGEN):

The R₁ moiety as defined in Formula (III) is introduced per Method "B"described for the preparation of the compounds of Formula (II) above.The protected oxyphenbutazone thus obtained is then reacted with acompound of the formula ##STR8## as described earlier in Method "A" ofFormual (III) to obtain the final product.

In all the above reaction schemes for the preparation of the compoundsof Formula (I) through (III) stoichiometric amounts of each reactant areemployed unless otherwise indicated.

It should be noted that in those instances where transient derivativesof oxyphenbutazone of the Formula (II) and (III) are prepared, twoisomers having the following formula can form:

ISOMERS FOR THE COMPOUNDS OF FORMULA (II) ##STR9## ISOMERS FOR THECOMPOUNDS OF FORMULA (III) ##STR10##

In the above formulas, R₁, R₂, R₄, and R₅ are defined as above.

No attempts were made to separate these isomers because a possiblemixture of the isomers would serve the same purpose, i.e., deliveryingoxyphenbutazone in the manner described in this application.

Without further elaboration, it is believed that one skilled in the artcan, using the preceding description, utilize the present invention toits fullest extent. The following preferred specific embodiments are,therefore, to be construed as merely illustrative, and not limitative ofthe remainder of the specification and claims in any way whatsoever.Unless otherwise indicated, all references to temperature denotesCentigrade.

EXAMPLE 1 1,2-DIPHENYL-4-BUTYL-5-(3'-CARBOXYPYRIDYL)-4-PYRAZOLIN-3-ONE

Phenylbutazone (1,2-diphenyl-3,5-pyrazolidinedione; 11.00 g, 0.035 mole)was treated with 11.55 g (0.055 mole) of trifluoroacetic anhydride. Theresulting solid suspension was shaken or mechanically stirred until ahomogeneous solution was obtained, then it was stirred with a magneticstirrer at room temperature in a tightly closed flask for one hour. Thesolution was concentrated in vacuo for one hour and the oily residueobtained was dissolved in 50 ml of acetone and allowed to react with12.5 g (0.055 mole) of nicotinic anhydride. The initial suspensionbecame homogeneous after 0.25 hours with concomitant formation of ayellow color. After an additional one hour at room temperature, theyellow solution was concentrated in vacuo and the residue was dissolvedin 200 ml of dichloromethane. The dichloromethane solution was extractedfirst with an aqueous sodium bicarbonate solution (12.2 g, 0.145 mole in150 ml), then with an aqueous sodium hydroxide solution (28 g, 0.07 molein 56 ml) and subsequently dried over sodium sulfate. Thedichloromethane solution was concentrated in vacuo and the residue wascrystallized from dichloromethane petroleum ether bp 30-60° C to give11.16 g (mp 139-141° C, 77.5% yield) of the title compound.

Anal. Calcd for C₂₅ H₂₃ N₃ O₃ : C, 72.62; H, 5.61; N, 10.16. Found: C,72.39; H, 5.64; N, 9.98.

EXAMPLE 21-(4'-BENZOYLOXYPHENYL)-2-PHENYL-4-BUTYL-5-BENZOYLOXY-4-PYRAZOLIN-3-ONEand1-PHENYL-2-(4'-BENZOYLOXYPHENYL)-4-BUTYL-5-BENZOYLOXY-4PYRAZOLIN-3-ONE

A dichloromethane (10 ml) solution containing 1.12 g (8.0 mmole) ofbenzoyl chloride was added to a dichloromethane (50 ml) solutioncontaining 0.81 g (8.0 mmole) of triethylamine and 1.25 g (3.85 mmole)of oxyphenbutazone [1-phenyl-2-(4'hydroxyphenyl)-3,5-pyrazolidinedione].The resulting solution warmed immediately, and after one hour at roomtemperature TLC (silica gel, ether) analysis of the reaction mixtureshowed that only one component could be observed. The solution waswashed with water (100 ml) and the dichloromethane layer was separated,dried over sodium sulfate and concentrated in vacuo. The residue wascrystallized from dichloromethane-heptane to give 1.81 g (88% yield) ofa white solid which gave a wide melting point range due to the fact thatit was a mixture of the title compounds.

Anal. Calcd for C₃₃ H₂₈ N₂ O₅ : C, 74.42; H, 5.29; N, 5.24. Found: C,74.58; H, 5.41; N, 5.06.

EXAMPLE 31-PHENYL-2-(4'-ACETYLOXYPHENYL)-4-BUTYL-5-PIVALYLOXY-4-PYRAZOLIN-3-ONEand1-(4'-ACETYLOXYPHENYL)-2-PHENYL-4-BUTYL-5-PIVALYLOXY-4-PYRAZOLIN-3-ONE

First, 1-Phenyl-2-(4'-acetyloxyphenyl)-3,5-pyrazolidinedione wasprepared as follows. Oxyphenbutazone (1.00 g, 3.1 mmole) was suspendedin 4 ml of glacial acetic acid and allowed to react with 2 ml of acetylchloride at room temperature overnight. The solution was concentrated invacuo at 86° C to give a white residue (mp 126-130° C). The residue wascrystallized from chloroformheptane (6:50) with cooling to give 0.81 g(mp 132-134° C, 71% yield, lit., R. Pfester and F. Hafliger, HelvecticaChemica Acta, 40, 395 (1957) mp 135-137° C from methanol) of1-phenyl-2-(4'-acetyloxyphenyl)-3,5-pyrazolidinedione.

Anal. Calcd for C₂₁ H₂₂ N₂ O₄ : C, 68.83; H, 6.05; N, 7.65. Found: C,69.08; H, 6.01; N, 7.38.

Next, the Thallium (I) salt of1-phenyl-2-(4'-acetyloxyphenyl)-3,5-pyrazolidinedione(acetyloxyphenbutazone; 0.77 g, 2.1 mmole) was partially suspended in 50ml of dry ether into which there was added 0.52 g (2.1 mmole) ofThallium (I) ethoxide dissolved in 10 ml of dry ether. A precipitateformed immediately. The suspension was stirred at room temperature for 2hours and then the suspension was filtered and the residue was dried togive 1.11 g (mp 170-175° C (dec.), 93% yield) of the white solidThallium (I) salt of acetyloxyphenbutazone. The Thallium (I) salt wasresuspended in dry ether (50 ml) and 0.21 g (1.9 mmole) of pivalylchloride dissolved in 10 ml of dry ether was added to the suspension.The suspension was stirred overnight at room temperature and then it wasfiltered and the filtrate concentrated in vacuo to give an oil. The oilwas partially crystallized from dichloromethane-heptane-ether to give0.15 g (mp 151-158° C) of a white solid which was shown to contain threecomponents upon analysis by TLC analysis. The major component wasseparated on a preparative TLC plate (silica gel, heptane-ether 1:1) togive the title compounds (mp 156-158° C).

Anal. Calcd for C₂₆ H₃₀ N₂ O₅ : C, 69.31; H, 6.71; N, 6.22. Found: C,69.03; H, 6.77; N, 6.11.

EXAMPLE 4 1,2-DIPHENYL-4-BUTYL-5-PIVALYLOXYMETHOXY-4-PYRAZOLIN-3-ONE and1,2-DIPHENYL-4-BUTYL-4-PIVALYLOXYMETHYL-3,5-PYRAZOLIDINEDIONE

Potassium carbonate (2.26 g, 0.016 mole) was suspended in an acetone(125 ml) solution of phenylbutazone and the suspension was refluxedovernight. The next day pivalyloxymethyl chloride (4.99 g, 0.033 mole)was added to the resulting solution and the solution was refluxedovernight. The suspension was cooled and filtered; the residue (2.00 g,83%) was potassium chloride. The filtrate was concentrated in vacuo andthe residue was suspended in ether, then filtered. The residue waswashed with ether until the washings did not contain any product by TLC.The residue from the ether suspension was the potassium salt ofphenylbutazone (2.25 g, 20%). The ether was then concentrated in vacuoand the residue was absorbed on silica gel and chromatographed onneutral silica gel (CC-7, Mallinckrodt) using petroleum ether bp 30-60°C - ether (1:1) as the eluent to give two fractions. The first fraction(Rf 0.46, silica gel, heptane-ether, 1:1) was crystallized fromheptane-petroleum ether bp 30-60° C, 1:1 to give 0.63 g (mp 116- 117° C,5% yield) of1,2-diphenyl-4-butyl-4-pivalyloxymethyl-3,5-pyrazolidinedione. nmr(CDCl₃) δ 4.40 (S, 2, ##STR11##

Anal. Calcd for C₂₅ H₃₀ N₂ O₄ : C, 71.07, H, 7.16; N, 6.63. Found: C,70.98; H, 7.20; N, 6.63.

The second fraction (Rf 0.26, silica gel, heptane-ether, 1:1) wascrystallized from heptane-petroleum ether, bp 30-60° C to give 5.61 g(mp 83-85° C, 41% yield) of1,2-diphenyl-4-butyl-5-pivalyloxymethoxy-4-pyrazolin-3-one. nmr (CDCl₃)δ 5.75 ##STR12##

Anal. Calcd for C₂₅ H₃₀ N₂ O₄ : C, 71.07; H, 7.16; N, 6.63. Found: C,71.22; H, 7.25; N, 6.74.

EXAMPLE 51,2-DIPHENYL-4-BUTYL-5-(4'-METHYLPHENYLSULFONYLOXY)-4-PYRAZOLIN-3-ONE

First, the Thallium (I) salt of phenylbutazone was prepared. Thallium(I) ethoxide (2.24 g. 9mmole) was dissolved in ether (100 ml) andallowed to react with 2.84 g (9.2 mmole) of phenylbutazone. The whitesuspension was stirred at room temperature for one hour then filteredand the residue was dried in a vacuum desiccator to give 4.55 g (mp194-202° C (dec.), 100% yield) of the Thallium (I) salt ofphenylbutazone.

Anal. Calcd for C₁₉ H₁₉ N₂ O₂ Tl: C, 44.59; H, 3.74. Found: C, 44.26; H,3.93.

Then, p-Toluenesulfonyl chloride (0.95 g, 5.0 mmole) was allowed toreact with a dimethylformamide (20 ml) suspension of the Thallium (I)salt of phenylbutazone. Within a few minutes the solvent became pink anda yellow solid, instead of the white Thallium (I) salt ofphenylbutazone, was observed suspended in the pink solution. Thesuspension was stirred overnight in a tightly sealed flask, then it wasdiluted with 100 ml of ether and filtered. The filtrate was concentratedin vacuo to remove the ether and the dimethylformamide was evaporatedunder a stream of nitrogen. The residue from the evaporation wassuspended in dichloromethane and filtered. Analysis of the filtrate byTLC showed that it contained only one major component. Thedichloromethane was evaporated in vacuo and the residue was crystallizedfrom ether to give 0.76 g (mp 112-121° C, 33% yield) of yellow crystalswhich contained only one component by TLC analysis. Recrystallization ofthe yellow crystals gave analytically pure crystals, mp 125-127° C withspectral properties identical to the crystals, mp 112-121° C.

Anal. Calcd for C₂₆ H₂₆ N₂ O₄ S: C, 67.51; H, 5.66; N, 6.06. Found: C,67.65; H, 5.74; N, 5.89.

EXAMPLE 6 1,2-DIPHENYL-4-BUTYL-5-ACETYLOXY-4-PYRAZOLIDIN-3-ONE

The title compound was prepared as in Example 1 except that thedichloromethane solution of the reaction product was extracted with thesodium bicarbonate solution only. The title compound was crystallizedfrom dichloromethane-petroleum ether, bp 30-60° C to give whitecrystals, mp 49-51° C in 54% yield.

Anal. Calcd for C₂₁ H₂₂ N₂ O₃ : C, 71.97; H, 6.33; N, 7.99. Found: C,71.79; N, 6.19; N, 8.16.

If the dichloromethane solution of the reaction product was notextracted with any base but crystallized from dichloromethane-petroleumether bp 30-60° C,1,2-diphenyl-4-butyl-5-hydroxy-5-trifluoroacetyloxy-3-acetyloxy-3-pyrazolinewas obtained in 70% yield as clear colorless crystals mp 63-66° C.

Anal. Calcd for C₂₃ H₂₃ N₂ O₅ F₃ : C, 59.47; H, 4.99; N, 6.03; F, 12.27.Found: C, 59.54; H, 5.02; N, 6.18; F, 12.24.

EXAMPLE 71,2-DIPHENYL-4-BUTYL-5-(N,N-DIMETHYLCARBAMOYLOXY)-4-PYRAZOLIDIN-3-ONE

An acetone (75 ml) solution of the potassium salt of phenylbutazone(2.34 g, 6.8 mmole) was allowed to react with 0.74 g (6.9 mmole) ofN,N-dimethylcarbamoyl chloride at reflux for 48 hours. The acetonesuspension was concentrated in vacuo and the residue was suspended indichloromethane. The dichloromethane suspension was extracted twice with20 ml of 0.1 N sodium hydroxide, then it was dried over sodium sulfateand concentrated in vacuo. The residue was crystallized fromdichloromethane-hexane (3:50) to give 1.25 g (mp 136-137.5° C, 48%yield) of the title compound.

Anal. Calcd for C₂₂ H₂₅ N₃ O₃ : C, 69.63; H, 6.44; N, 11.07. Found: C,69.53; H, 6.41; N, 10.92.

EXAMPLE 8 1,2-DIPHENYL-4-BUTYL-5-PIVALYLOXY-4-PYRAZOLIDIN-3-ONE

First, the Thallium (I) salt was prepared in the same way as in Example5, then 5.12 g (10 mmole) of the Thallium (I) salt of phenylbutazone wassuspended in ether (100 ml) and allowed to react with 1.20 g (10 mmole)of pivalyl chloride. The suspension was stirred at room temperature for6 hours, filtered and the filtrate was concentratec in vacuo. Theresidue was titrated with petroleum ether, bp 30-60° C to give 2.95 g(mp 114-115° C, 75% yield) of the title compound.

Anal. Calcd for C₂₄ H₂₈ N₂ O₃ : C, 73.44; H, 7.19; N, 7.14. Found: C,73.40; H, 7.06; N, 7.18.

EXAMPLE 9 1,2-DIPHENYL-4-BUTYL-5-(N,NDIETHYLCARBAMOYLMETHOXY)-4-PYRAZOLIDIN-3-ONE and1,2-DIPHENYL-4-BUTYL-4-(N,N-DIETHYLCARBAMOYLMETHYL)-3,5-PYRAZOLIDINEDIONE

N,N-Diethylchloroacetamide (3.00 g, 20 mmole) was added to an acetone(60 ml) solution containing 6.0 g (19.5 mmole) of phenylbutazone and1.38 g (10 mmole) of potassium carbonate. The suspension was refluxedfor 48 hours, then it was filtered, and the residue (1.20 g, 81% yieldof potassium chloride) was washed with acetone (100 ml). The acetonefiltrate was concentrated in vacuo, and the residue therefrom wastitrated with dichloromethane. The dichloromethane suspension wasfiltered to give 1.16 g (17% yield) of the postassium salt ofphenylbutazone as a white residue. The dichloromethane filtrate wasconcentrated in vacuo and the residue (7.30 g) was suspended in ether(50 ml). The ether suspension was filtered and the residue was washedwith 20 ml of ether, then dried in a vacuum desiccator to give 3.50 g(mp 134-135° C, 43% yield) of the C-alkylated product: nmr (CDCl₃) δ 3.1S, 2, ##STR13##

Anal. Calcd for C₂₅ H₃₁ N₃ O₃ : C, 71.23; H, 7.41; N, 9.97. Found: C,71.14; H, 7.26; N, 10.00.

The ether filtrate was absorbed on silica gel and chromatographed onneutral silica gel (89 g) using ether as the eluent to give twofractions. The first fraction (Rf 0.33, silica gel, ether) was theC-alkylated product: 1.16 g, mp 129.5-132° C, 13% yield. The secondfraction (Rf 0.13, silica gel, ether) was the O-alkylated product: 2.25g of a viscous oil, 22% yield. The O-alkylated was finally crystallizedfrom dichloromethane-heptane, 10:60 to give 0.81 g (mp 80.5-82° C, 10%yield) of white needles which had spectral properties identical with thecrude viscous oil: nmr (CDCl₃) δ 4.73 (S, 2, ##STR14##

Anal. Calcd for C₂₅ H₃₁ N₃ O₃ : C, 71.23; H, 7.41; N, 9.97. Found: C,71.15; H, 7.41; N, 9.82.

The preceding examples can be repeated with similar success by simplysubstituting the appropriate generically or specifically describedreactants and/or operating conditions of this invention for those usedin the preceding examples.

The pro-drug forms of this invention are suitably administered in oraldosage form, such as by tablet or capsule, by combining the same in atherapeutic amount of any oral pharmaceutically acceptable inertcarrier, such as lactose, starch (pharmaceutical grade), dicalciumphosphate, calcium sulfate, Kaolin, mannitol and powdered sugar. Inaddition, when required, suitable binders, lubricants, disintegratingagents, and coloring agents can also be added. Typical binders include,without limitation, starch, gelatin, sugars such as sucrose, molasses,and lactose, natural and synthetic gums, such as acacia, sodiumalginate, extract of Irish moss, carboxymethylcellulose,methylcellulose, and polyvinylpyrrolidone, polyethylene glycol,ethylcellulose and waxes. Typical lubricants for use in these dosageforms can include, without limitation, boric acid, sodium benzoate,sodium acetate, sodium chloride, leucine and polyethylene glycol.Suitable disintegrators can include, without limitation, starch,methylcellulose, agar, bentonite, cellulose and wood products, alginicacid, guar gum, citris pulp, carboxymethylcellulose, and sodium laurylsulfate. Optionally, if desired, a conventionally, pharmaceuticallyacceptable dye can be incorporated into the oral dosage unit form, e.g.,any of the standard FD&C dyes.

Any skilled artisan concerned with the subject matter of this inventioncan prepare these oral dosage forms by simply referring to the oraldosage form preparatory procedure outlined in "REMINGTON'SPHARMACEUTICAL SCIENCES," Fourteenth Edition (1970), pages 1659 through1698 inclusive.

While the therapeutic dosage range for the compounds of this inventionwill vary with the size and needs of the patient, generally speaking,the daily dosage range, on an equivalent basis, will mimic that forphenylbutazone and oxyphenbutazone. See Physicians' Desk Reference,Twenty-eighth Edition (1974), pages 772-774.

From the foregoing description, one of ordinary skill in the art caneasily ascertain the essential characteristics of this invention, andwithout departing from the spirit and scope thereof, can make variouschanges and modifications of the invention to adapt it to various usagesand conditions. As such, such changes and modifications are properly,equitably, and intended to be, within the full range of equivalence ofthe following claims.

What we claim is:
 1. The intermediatecompound:1,2-Diphenyl-3,5-ditrifluoroacetyloxy-4-butyl-5-hydroxy-3-pyrazoline.